The density and reproductive biology of the Fiddler Crab Uca sindensis (Alcock, 1900) (Crustacea: Ocypodidae) in intertidal zone of Shatt Al-Basrah river –Khor Al-Zubair, Iraq

Abstract

The density and reproductive biology of Uca sindensis were studied inintertidal zone of Khor Al-Zubair, south of Shatt Al-Basrah river, Basrah, Iraq.The crabs were collected randomly three 0.25m2 quadrates during low tideperiods from November 2014 to October 2015. Density of crabs, sex ratio,distribution, population structure, diameter burrow, breeding season andfecundity were investigated. The results showed that crabs population fluctuatedand depended on the months of the year. Crabs density in study area was(181ind/ m2 in April 2015) and (19 ind./m2 in December 2015). The CW offemales ranged from 4 to 13.5 mm and of males from 5 to 16 mm indicatingsexual dimorphism. The relationship between Carapace width (CW) × Carapace height (CH) was positive in males and females. The equation (Log CH=Log-4.644+4.362LogCW) for males (P 0.05), however the monthly sex ratio wasdifferent from expected 1:1(χ test, P<0.05). Breeding took place during warmseason of March to October 2015. The regression analysis showed that thenumber of eggs increased linearly with the increase of carapace width (r2=0.775, n=38). It was concluded that some factors of temperature, Salinity andTOM in sediment affected at density growth and reproduction pattern in U.sindensis.